The TCA9534 is a 16-pin device that provides 8 bits of general purpose parallel input/output (I/O) expansion for the two-line bidirectional I2C bus (or SMBus) protocol. The device can operate with a power supply voltage ranging from 1.65 V to 5.5 V.

The device supports both 100-kHz (Standard-mode) and 400-kHz (Fast-mode) clock frequencies. I/O expanders such as the TCA9534 provide a simple solution when additional I/Os are needed for switches, sensors, push-buttons, LEDs, fans, and other similar devices.